Agents Of Infections Research Articles

Investigating the Effectiveness of Ceragenins against Acinetobacter baumannii to Develop New Antimicrobial and Anti-Adhesive Strategies.

A growing body of experimental data indicates that ceragenins (CSAs), which mimic the physicochemical properties of the host's cationic antimicrobial peptide, hold promise for the development of a new group of broad-spectrum antimicrobials. Here, using a set of in vivo experiments, we assessed the potential of ceragenins in the eradication of an important etiological agent of nosocomial infections, Acinetobacter baumannii. Assessment of the bactericidal effect of ceragenins CSA-13, CSA-44, and CSA-131 on clinical isolates of A. baumannii (n = 65) and their effectiveness against bacterial cells embedded in the biofilm matrix after biofilm growth on abiotic surfaces showed a strong bactericidal effect of the tested molecules regardless of bacterial growth pattern. AFM assessment of bacterial cell topography, bacterial cell stiffness, and adhesion showed significant membrane breakdown and rheological changes, indicating the ability of ceragenins to target surface structures of A. baumannii cells. In the cell culture of A549 lung epithelial cells, ceragenin CSA-13 had the ability to inhibit bacterial adhesion to host cells, suggesting that it interferes with the mechanism of bacterial cell invasion. These findings highlight the potential of ceragenins as therapeutic agents in the development of antimicrobial strategies against bacterial infections caused by A. baumannii.

Discovery and Optimization of Novel SaFabI Inhibitors as Specific Therapeutic Agents for MRSA Infection.

As the rate-limiting enzyme in fatty acid biosynthesis, Staphylococcus aureus enoyl-acyl carrier protein reductase (SaFabI) emerges as a compelling target for combating methicillin-resistant S. aureus (MRSA) infections. Herein, compound 1, featuring a 4-(1H-benzo[d]imidazol-2-yl)pyrrolidin-2-one scaffold, was identified as a potent SaFabI inhibitor (IC50 = 976.8 nM) from an in-house library. Subsequent optimization yielded compound n31, with improved inhibitory efficacy on enzymatic activity (IC50 = 174.2 nM) and selective potency against S. aureus (MIC = 1-2 μg/mL). Mechanistically, n31 directly inhibited SaFabI in cellular contexts. Moreover, n31 exhibited favorable safety and pharmacokinetic profiles, and dose-dependently treated MRSA-induced skin infections, outperforming the approved drug, linezolid. The chiral separation of n31 resulted in (S)-n31, with superior activities (IC50 = 94.0 nM, MIC = 0.25-1 μg/mL) and in vivo therapeutic efficacy. In brief, our research proposes (S)-n31 as a promising candidate for SaFabI-targeted therapy, offering specific anti-S. aureus efficacy and potential for further development.

Обзор эффективности и безопасности препарата Канефрон® Н при лечении и профилактике инфекций мочевыводящих путей у различных групп пациентов.

Introduction. The growth of antibiotic-resistant strains of microorganisms that cause urological infections, especially uropathogenic Escherichia coli, the main causative agent of uncomplicated urinary tract infections, requires the search for alternative antimicrobial treatment methods. The discovery of the urine microbiome explains the concept of «asymptomatic bacteriuria», which in most cases does not require the use of antibiotics. The effectiveness of herbal preparations in the treatment and prevention of urinary tract infections has been proven by their traditional use over many years, as well as by scientific research in recent decades. Materials and methods. The presented review summarizes the results of the use of the drug Canephron® N over the past decade, published in the international databases PubMed, Embase, Cochrane Library, ClinicalTrials.gov, articles in Russian from the eLibrary.ru database and their bibliography. Data from randomized, observational clinical studies in adult patients and children are presented. The studies were conducted in patients with infectious and inflammatory diseases of the kidneys, bladder and urinary tract. Results. 32 publications in both Russian and English were analyzed. Publications are grouped together: the use of Canephron® N in the treatment and prevention of urinary tract infections (cystitis and pyelonephritis) in adults; in children; in pregnant women; after urological interventions. The quality of the studies and side effects after using Canephron® N were discussed. Conclusions. The effectiveness and safety of Canephron® N in the treatment and prevention of urological diseases has been proven.

Candida parapsilosis: Heterogeneous and strain-specific expression of secreted aspartic proteases (Sapp1 and Sapp2).

The increasing prevalence of Candida parapsilosis as a causative agent of fungal infections underscores the need to comprehensively understand its virulence factors. Secreted aspartic proteases (Saps) play a significant role in adhesion events, promoting biofilm formation, causing tissue damage and evading the host's immune response. In C. parapsilosis, three Saps have been identified: Sapp1, Sapp2 and Sapp3. The present study investigates the production dynamics of Sapp1 and Sapp2 across 10 clinical isolates of C. parapsilosis using various approaches. Each fungal isolate demonstrated the capability to utilize bovine serum albumin (BSA) as the sole nitrogen source, as evidenced by its degradation in a cell-free culture medium, forming low molecular mass polypeptides. Interestingly, the degradation of different proteinaceous substrates, such as BSA, human serum albumin (HSA), gelatin and hemoglobin, was typically isolate-dependent. Notably, higher proteolysis of HSA compared to BSA, gelatin and hemoglobin was observed. A quantitative assay revealed that the cleavage of a peptide fluorogenic substrate (cathepsin D) was isolate-specific, ranging from 44.15 to 270.61 fluorescence arbitrary units (FAU), with a mean proteolysis of 150.7 FAU. The presence of both Sapp1 and Sapp2 antigens on the cell surface of these fungal isolates was confirmed through immunological detection employing specific anti-Sapp1 and anti-Sapp2 antibodies. The surface levels of Sapp1 were consistently higher, up to fourfold, compared to Sapp2. Similarly, higher levels of Sapp1 than Sapp2 were detected in fungal secretions. This study provides insights into the dynamic expression and regulation of Sapps in C. parapsilosis, highlighting a known virulence factor that is considered a potential target for drug development against this increasingly prominent pathogen.

Innovative Design Strategy and Research Progress of Anti Human Papilloma Virus Infection Agents

This review summarized the mechanism of a novel fusion protein (PHPV fusion protein) containing membrane penetrating peptide and oligopeptide-1 (EGF). The new PHPV fusion protein contains two kinds of polypeptides: membrane penetrating peptide and oligopeptide-1, so it has a good function of preventing and treating HPV virus. PHPV fusion protein not only has the multi effect function of membrane penetrating peptide and oligopeptide-1, but also the negative charge (anion) C-terminal of the cross-linked and fused new protein surface interacts with the positive charge (cation) N-terminal on HPV particles. Through the combination of the N-terminal of the positive charge on its surface with the negative charge of the hydrophobic region in the middle and the C-terminal of the recognition region site containing peptidase, the membrane translocation signal is coupled with the NLS of the nuclear localization signal, thus blocking the invasion of human papillomavirus into host cells. Through the interaction of cell membrane, it can penetrate the natural barrier of cell membrane and play a role in destroying the viral membrane shell to inactivate the virus, so as to prevent cervical precancerous lesions and treat HPV infection. PHPV fusion protein can repair damaged cells, enhance the elasticity of loose vaginal mucosa, tighten the inner wall of the vagina, improve the vaginal wetness, and reduce the vaginitis reaction.

Lameness in Cattle-Etiopathogenesis, Prevention and Treatment.

The aim of this review was to analyse the health problem of lameness in dairy cows by assessing the health and economic losses. This review also presents in detail the etiopathogenesis of lameness in dairy cattle and examples of its treatment and prevention. This work is based on a review of available publications. In selecting articles for the manuscript, the authors focused on issues observed in cattle herds during their clinical work. Lameness in dairy cattle is a serious health and economic problem around the world. Production losses result from reduced milk yield, reduced feed intake, reproductive disorders, treatment costs, and costs associated with early culling. A significant difficulty in the control and treatment of lameness is the multifactorial nature of the disease; causes may be individual or species-specific and may be associated with the environment, nutrition, or the presence of concomitant diseases. An important role is ascribed to infectious agents of both systemic and local infections, which can cause problems with movement in animals. It is also worth noting the long treatment process, which can last up to several months, thus significantly affecting yield and production. Given the high economic losses resulting from lameness in dairy cows, reaching even >40% (depending on the scale of production), there seems to be a need to implement extensive preventive measures to reduce the occurrence of limb infections in animals. The most important effective preventive measures to reduce the occurrence of limb diseases with symptoms of lameness are periodic hoof examinations and correction, nutritional control, and bathing with disinfectants. A clean and dry environment for cows should also be a priority.

Antibiotyping, RAPD- and ERIC-PCR fingerprinting of Klebsiella pneumoniae clinical isolates at a tertiary reference hospital in Denpasar, Bali, Indonesia.

Klebsiella pneumoniae is a healthcare-associated infections agent and could be an extended spectrum β-lactamase (ESBL) producer. Understanding the transmission of this bacterium in a hospital setting needs accurate typing methods. An antibiogram is used to detect the resistance pattern of the isolates. Random Amplified Polymorphic DNA (RAPD) and Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR are rapid, technically simple, and easy-to-interpret DNA typing methods. This study aimed to evaluate the use of antibiotyping, RAPD-, and ERIC-PCR to investigate the heterogeneity of K. pneumoniae isolated from clinical specimens. The antibiograms of 46 K. pneumoniae clinical isolates were determined by Vitek® 2 Compact. All isolates underwent RAPD-PCR using AP4 primer and ERIC-PCR using ERIC-2 primer. The dendrogram was generated using the GelJ software and analyzed to determine its similarity. The analysis of antibiogram and the molecular typing diversity index was calculated using the formula of the Simpson's diversity index. About 71.7% of the isolates were ESBL-producers, and more than 80% of isolates were susceptible to amikacin, ertapenem, and meropenem. The antibiotyping produced 32 diverse types with DI = 0.964. In addition, the RAPD-PCR produced 47 different types with DI = 1, while ERIC-PCR was 46 (DI=0.999). Antibiotyping, RAPD- and ERIC-PCR showed powerful discrimination power among the isolates, supported the diversity of K. pneumoniae isolates in current study. These combination could be promising tools for clonal relationship determination, including in tracking the transmission of the outbreak's agent in hospital setting.

Evolution of mutations in the ftsI gene leading to amino acid substitutions in PBP3 in Haemophilus influenzae strains under the selective pressure of ampicillin and cefuroxime

BackgroundAminopenicillins are recommended agents for non-invasive Haemophilus influenzae infections. One of the mechanisms of resistance to β-lactams is the alteration of the transpeptidase region of penicillin binding protein 3 (PBP3) which is caused by mutations in the ftsI gene. It was shown that exposure to beta-lactams has a stimulating effect on increase of prevalence of H. influenzae strains with the non-enzymatic mechanism of resistance. ObjectivesThe aim of our study was to compare the mutational potential of ampicillin and cefuroxime in H. influenzae strains, determination of minimum inhibitory concentration and the evolution of mutations over time, focusing on amino acid substitutions in PBP3. Methods30 days of serial passaging of strains in liquid broth containing increasing concentrations of ampicillin or cefuroxime was followed by whole-genome sequencing. ResultsOn average, cefuroxime increased the minimum inhibitory concentration more than ampicillin. The minimum inhibitory concentration was increased by a maximum of 32 fold. Substitutions in the PBP3 started to appear after 15 days of passaging. In PBP3, cefuroxime caused different substitutions than ampicillin. ConclusionsOur experiment observed differences in mutation selection by ampicillin and cefuroxime. Selection pressure of antibiotics in vitro generated substitutions that do not occur in clinical strains in the Czech Republic.

Enhanced antibacterial activity of multi-walled carbon nanotubes loaded with hot-melt extruded Mulberry leaf silver nanoparticles

We suggest an antibacterial nanoplatform composed of multi-walled carbon nanotubes (MWCNTs) coated with mesoporous silica decorated with silver nanoparticles (AgNPs) via an N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD)-mediated method. In this system, the external mesoporous silica shell enhances the dispersion of MWCNTs to increase their contact area with bacterial cell walls. Meanwhile, the multiple mesoporous voids in the silica layer serve as a microreactor for on-site synthesis of small-sized and uniformly distributed AgNPs, thereby enhancing the antibacterial activity. Mulberry leaf (ML) extract was used to reduce Ag ions. In this process, hot melt extrusion (HME) was applied to increase the active ingredients of the ML extract. To prevent loss of ML components due to the heat and pressure applied during HME treatment, several excipients, including whey protein isolate, were mixed, and added. Compared with ML AgNPs and mesoporous silica-coated MWCNTs decorated with AgNPs (MWCNT-Ag), the MWCNT-Ag@ML (MWCNT-ML) exhibited stronger antibacterial against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and methicillin-resistant S. aureus (MRSA). Therefore, this nano platform is a potential antibacterial agent and therapeutic agent for drug-resistant infections.

In vivo efficacy of phage cocktails against carbapenem resistance Acinetobacter baumannii in the rat pneumonia model.

Acinetobacter baumannii, an opportunistic pathogen, poses a significant threat in intensive care units, leading to severe nosocomial infections. The rise of multi-drug-resistant strains, particularly carbapenem-resistant A. baumannii, has created formidable challenges for effective treatment. Given the prolonged development cycle and high costs associated with antibiotics, phages have garnered clinical attention as an alternative for combating infections caused by drug-resistant bacteria. However, the utilization of phage therapy encounters notable challenges, including the narrow host spectrum, where each phage targets a limited subset of bacteria, increasing the risk of phage resistance development. Additionally, uncertainties in immune system dynamics during treatment hinder tailoring symptomatic interventions based on patient-specific states. In this study, we isolated two A. baumannii phages from wastewater and conducted a comprehensive assessment of their potential applications. This evaluation included sequencing analysis, genome classification, pH and temperature stability assessments, and in vitro bacterial inhibition assays. Further investigations involved analyzing histological and cytokine alterations in rats undergoing phage cocktail treatment for pneumonia. The therapeutic efficacy of the phages was validated, and transcriptomic studies of rat lung tissue during phage treatment revealed crucial changes in the immune system. The findings from our study underscore the potential of phages for future development as a treatment strategy and offer compelling evidence regarding immune system dynamics throughout the treatment process.IMPORTANCEDue to the growing problem of multi-drug-resistant bacteria, the use of phages is being considered as an alternative to antibiotics, and the genetic safety and application stability of phages determine the potential of phage application. The absence of drug resistance genes and virulence genes in the phage genome can ensure the safety of phage application, and the fact that phage can remain active in a wide range of temperatures and pH is also necessary for application. In addition, the effect evaluation of preclinical studies is especially important for clinical application. By simulating the immune response situation during the treatment process through mammalian models, the changes in animal immunity can be observed, and the effect of phage therapy can be further evaluated. Our study provides compelling evidence that phages hold promise for further development as therapeutic agents for Acinetobacter baumannii infections.

Prevalence of Hepatozoon canis infection in dogs from the area of Lublin Voivodship

Canine hepatozoonosis is a tick-borne protozoal disease. Two species of Hepatozoon may infect dogs: Hepatozoon americanum and H. canis. The aim of the paper was to attempt to detect the genetic material of H. canis in blood samples collected from dogs suspected to suffer from tick-borne diseases. 107 samples were tested with the use of the real-time PCR technique (Vcheck M Bionote analyser), of which 99 were collected from dogs which never left Polish territory (group 1) and 8 from dogs which spent the holidays with their owners in Turkey (group 2). DNA of H. canis was detected in 1 dog in group 1 (with Ixodes ricinus infestation), and in 2 dogs in group 2 (with Ripicephalus sanguineus infestation). The results obtained indicate that infections with H. canis should be taken into account and included in the differential diagnosis of vector-borne diseases in dogs in Poland, and the accurate identification of the infection agent is crucial for developing the correct treatment regimen and prognosis.

ER-mitochondria association negatively affects wound healing by regulating NLRP3 activation

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common causative agent of acute bacterial skin and skin-structure infections (ABSSSI), one of the major challenges to the health system worldwide. Although the use of antibiotics as the first line of intervention for MRSA-infected wounds is recommended, important side effects could occur, including cytotoxicity or immune dysregulation, thus affecting the repair process. Here, we show that the oxazolidinone antibiotic linezolid (LZD) impairs wound healing by aberrantly increasing interleukin 1 β (IL-1β) production in keratinocytes. Mechanistically, LZD triggers a reactive oxygen species (ROS)-independent mitochondrial damage that culminates in increased tethering between the endoplasmic reticulum (ER) and mitochondria, which in turn activates the NLR family pyrin domain-containing 3 (NLRP3) inflammasome complex by promoting its assembly to the mitochondrial surface. Downregulation of ER-mitochondria contact formation is sufficient to inhibit the LZD-driven NLRP3 inflammasome activation and IL-1β production, restoring wound closure. These results identify the ER-mitochondria association as a key factor for NLRP3 activation and reveal a new mechanism in the regulation of the wound healing process that might be clinically relevant.

Characterization of bacteriophages infecting multidrug-resistant uropathogenic Escherichia coli strains

Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infections, and strains that are resistant to antibiotics are a major problem in treating these infections. Phage therapy is a promising alternative approach that can be used to treat infections caused by polyresistant bacterial strains. In the present study, 16 bacteriophages isolated from sewage and surface water were investigated. Phage host specificity was tested on a collection of 77 UPEC strains. The phages infected 2–44 strains, and 80% of the strains were infected by at least one phage. The susceptible E. coli strains belonged predominantly to the B2 phylogenetic group, including strains of two clones, CC131 and CC73, that have a worldwide distribution. All of the phages belonged to class Caudoviricetes and were identified as members of the families Straboviridae, Autographiviridae, and Drexlerviridae and the genera Kagunavirus, Justusliebigvirus, and Murrayvirus. A phage cocktail composed of six phages – four members of the family Straboviridae and two members of the family Autographiviridae – was prepared, and its antibacterial activity was tested in liquid medium. Complete suppression of bacterial growth was observed after 5–22 hours of cultivation, followed by partial regrowth. At 24 hours postinfection, the cocktail suppressed bacterial growth to 43–92% of control values. Similar results were obtained when testing the activity of the phage cocktail in LB and in artificial urine medium. The results indicate that our phage cocktail has potential to inhibit bacterial growth during infection, and they will therefore be preserved in the national phage bank, serving as valuable resources for therapeutic applications.

Ophthalmic Complications, Diagnosis, and Treatment of Congenital Human Cytomegalovirus Infection.

Background: Human cytomegalovirus (hCMV) is the most common etiological agent of congenital infections seen in newborns. Among the most commonly observed complications in children with congenital human cytomegalovirus infection are those affecting the visual system. Ocular complications of congenital CMV (cCMV) are a topic rarely addressed in the literature, which prompted the authors to update the available knowledge with the latest data. Methodology: English-language literature published between April 2000 and November 2023 (PubMed, NIH, Google Scholar) was analyzed for ocular complications of cCMV. The data obtained were categorized according to the ocular area involved and the incidence. A compilation of criteria for the symptomatic form of cCMV was also created. Results: The cCMV complications described in the literature affect all parts of the visual system: the anterior segment, the posterior segment, the posterior visual pathways, and the visual cortex. The most commonly described ocular complication of cCMV is choroidal and retinal scarring. Conclusions: Ophthalmic complications of cCMV can cause severe visual disturbances. Ophthalmic diagnosis in newborns should include hCMV PCR testing, which has the highest sensitivity and specificity. In the symptomatic form of cCMV, treatment should be instituted according to recommendations. A consensus should be established for screening of primary hCMV infection in pregnant women, the way in which to define the symptomatic form of cCMV, and the appropriateness and standards of treatment for primary hCMV infection in pregnant women.

A 14-amino acid cationic peptide Bolespleenin334-347 from the marine fish mudskipper Boleophthalmus pectinirostris exhibiting potent antimicrobial activity and therapeutic potential

Antimicrobial peptides (AMPs) are an important component of innate immunity in both vertebrates and invertebrates, and some of the unique characteristics of AMPs are usually associated with their living environment. The marine fish, mudskipper Boleophthalmus pectinirostris, usually live amphibiously in intertidal environments that are quite different from other fish species, which would be an exceptional source of new AMPs. In the study, an AMP named Bolespleenin334-347 was identified, which was a truncated peptide derived from a new functional gene found in B. pectinirostris, that was up-regulated in response to bacterial challenge. Bolespleenin334-347 had only 14 amino acid residues, including five consecutive arginine residues. It was found that the peptide had broad-spectrum antibacterial activity, good thermal stability and sodium ion tolerance. Bolespleenin334-347 killed Acinetobacter baumannii and Staphylococcus aureus by disrupting the structural integrity of the bacterial membrane, leading to leakage of the cellular contents, and inducing accumulation of bacterial endogenous reactive oxygen species (ROS). In addition, Bolespleenin334-347 effectively inhibited biofilm formation of A. baumannii and S. aureus and long-term treatment did not lead to the development of resistance. Importantly, Bolespleenin334-347 maintained stable activity against clinically multi-drug resistant bacterial strains. In addition, it was noteworthy that Bolespleenin334-347 showed superior efficacy to LL-37 and vancomycin in a constructed mouse model of MRSA-induced superficial skin infections, as evidenced by a significant reduction in bacterial load and more favorable wound healing. This study provides an effective antimicrobial agent for topical skin infections with potential therapeutic efficacy for infections with drug-resistant bacteria, including MRSA.

Antibacterial activity of avocado extract (Persea americana Mill.) against aminoglycoside-resistant Klebsiella pneumoniae strains

Klebsiella pneumoniae is an important etiological agent of nosocomial infections. This study focuses on the antibacterial activity of Persea Americana extract against K. pneumoniae strains containing aminoglycoside genes. Broth microdilution technique was used to examine the antibacterial activity of P. americana extract on K. pneumoniae isolates. The phenolic components of its leaves were analysed by the HPLC-DAD system. The binding potential of the major phytochemical component of the extract, chlorogenic acid, to the KsgA was investigated by molecular docking. The stability of the resulting enzyme-ligand complexes was also assessed through molecular dynamics simulation. The result obtained showed that P. americana extract had antibacterial activity on aminoglycoside resistant strains. The binding potential of chlorogenic acid (main phenolic compound) to KsgA was found to be higher than the binding of gentamicin. Since chlorogenic acid had lower binding energy and formed higher number of H-bonding as well as other interactions in the docking analysis. The higher binding potential of the major component with the enzyme that was involved in resistance development against aminoglycoside indicated its possible role in overturning the condition. Moreover, the molecular dynamics simulation study revealed that chlorogenic acid formed a complex with relatively higher stability. The higher binding potential of the major component with higher stability implied that the computational results confirmed the experimental findings.

Deficiency in non-classical major histocompatibility class II-like molecule, H2-O confers protection against Staphylococcus aureus in mice.

Staphylococcus aureus is a human-adapted pathogen that replicates by asymptomatically colonizing its host. S. aureus is also the causative agent of purulent skin and soft tissue infections as well as bloodstream infections that result in the metastatic seeding of abscess lesions in all organ tissues. Prolonged colonization, infection, disease relapse, and recurrence point to the versatile capacity of S. aureus to bypass innate and adaptive immune defenses as well as the notion that some hosts fail to generate protective immune responses. Here, we find a genetic trait that provides protection against this pathogen. Mice lacking functional H2-O, the equivalent of human HLA-DO, inoculated with a mouse-adapted strain of S. aureus, efficiently decolonize the pathogen. Further, these decolonized animals resist subsequent bloodstream challenge with methicillin-resistant S. aureus. A genetic approach demonstrates that T-cell dependent B cell responses are required to control S. aureus colonization and infection in H2-O-deficient mice. Reduced bacterial burdens in these animals correlate with increased titers and enhanced phagocytic activity of S. aureus-specific antibodies. H2-O negatively regulates the loading of high affinity peptides on major histocompatibility class II (MHC-II) molecules. Thus, we hypothesize that immune responses against S. aureus are derepressed in mice lacking H2-O because more high affinity peptides are presented by MHC-II. We speculate that loss-of-function HLA-DO alleles may similarly control S. aureus replication in humans.

Rapid discrimination methods for clinical and environmental strains of Aeromonas hydrophila and A. veronii biovar sobria using the N-terminal sequence of the flaA gene and investigation of antimicrobial resistance.

Although the genus Aeromonas inhabits the natural environment, it has also been isolated from hospital patient specimens as a causative agent of Aeromonas infections. However, it is not known whether clinical strains live in the natural environment, and if these strains have acquired antimicrobial resistance. In this study, we performed the typing of flagellin A gene (flaA) of clinical and environmental strains of Aeromonas hydrophila and A. veronii biovar sobria using Polymerase Chain Reaction (PCR) assay with newly designed primers. Detection rates of the clinical and environmental flaA types of A. hydrophila were 66.7% and 88.2%, and the corresponding rates for A. veronii biovar sobria were 66.7% and 90.9%. The PCR assays could significantly discriminate between clinical and environmental strains of both species in approximately 4 h. Also, among the 63 clinical Aeromonas strains used, only one extended-spectrum β-lactamase-producing bacteria, no plasmid-mediated quinolone resistance bacteria, and only four multidrug-resistant bacteria were detected. Therefore, the PCR assays could be useful for the rapid diagnosis of these Aeromonas infections and the monitoring of clinical strain invasion into water-related facilities and environments. Also, the frequency of drug-resistant Aeromonas in clinical isolates from Okinawa Prefecture, Japan, appeared to be low.

Epidemiological trends, antifungal drug susceptibility and SQLE point mutations in etiologic species of human dermatophytosis in Al-Diwaneyah, Iraq

Dermatophytes show a wide geographic distribution and are the main causative agents of skin fungal infections in many regions of the world. Recently, their resistance to antifungal drugs has led to an obstacle to effective treatment. To address the lack of dermatophytosis data in Iraq, this study was designed to investigate the distribution and prevalence of dermatophytes in the human population and single point mutations in squalene epoxidase gene (SQLE) of terbinafine resistant isolates. The identification of 102 dermatophytes isolated from clinical human dermatophytosis was performed through morphological and microscopic characteristics followed by molecular analysis based on ITS and TEF-1α sequencing. Phylogeny was achieved through RAxML analysis. CLSI M38-A2 protocol was used to assess antifungal susceptibility of the isolates to four major antifungal drugs. Additionally, the presence of point mutations in SQLE gene, which are responsible for terbinafine resistance was investigated. Tinea corporis was the most prevalent clinical manifestation accounting for 37.24% of examined cases of dermatophytosis. Based on ITS, T. indotineae (50.98%), T. mentagrophytes (19.61%), and M. canis (29.41%) was identified as an etiologic species. T. indotineae and T. mentagrophytes strains were identified as T. interdigitale based on TEF-1α. Terbinafine showed the highest efficacy among the tested antifungal drugs. T. indotineae and T. mentagrophytes showed the highest resistance to antifungal drugs with MICs of 2–4 and 4 μg/mL, while M. canis was the most susceptible species. Three of T. indotineae isolates showed mutations in SQLE gene Phe397Leu substitution. A non-previously described point mutation, Phe311Leu was identified in T. indotineae and mutations Lys276Asn, Phe397Leu and Leu419Phe were diagnosed in T. mentagrophytes XVII. The results of mutation analysis showed that Phe397Leu was a destabilizing mutation; protein stability has decreased with variations in pH, and point mutations affected the interatomic interaction, resulting in bond disruption. These results could help to control the progression of disease effectively and make decisions regarding the selection of appropriate drugs for dermatophyte infections.

Antibiotic resistance pattern of waterborne causative agents of healthcare-associated infections: A call for biofilm control in hospital water systems

BackgroundIn recent years, the global spread of antimicrobial resistance has become a concerning issue, often referred to as a “silent pandemic”. Healthcare-associated infections (HAIs) caused by antibiotic-resistant bacteria (ARB) are a recurring problem, with some originating from waterborne route. The study aimed to investigate the presence of clinically relevant opportunistic bacteria and antibiotic resistance genes (ARGs) in hospital water distribution systems (WDSs). MethodsWater and biofilm samples (n = 192) were collected from nine hospitals in Isfahan and Kashan, located in central Iran, between May 2022 and June 2023. The samples were analyzed to determine the presence and quantities of opportunistic bacteria and ARGs using cultural and molecular methods. ResultsStaphylococcus spp. were highly detected in WDS samples (90 isolates), with 33 % of them harboring mecA gene. However, the occurrences of E. coli (1 isolate), Acinetobacter baumannii (3 isolates), and Pseudomonas aeruginosa (14 isolates) were low. Moreover, several Gram-negative bacteria containing ARGs were identified in the samples, mainly belonging to Stenotrophomonas, Sphingomonas and Brevundimonas genera. Various ARGs, as well as intI1, were found in hospital WDSs (ranging from 14 % to 60 %), with higher occurrences in the biofilm samples. ConclusionOur results underscore the importance of biofilms in water taps as hotspots for the dissemination of opportunistic bacteria and ARG within hospital environments. The identification of multiple opportunistic bacteria and ARGs raises concerns about the potential exposure and acquisition of HAIs, emphasizing the need for proactive measures, particularly in controlling biofilms, to mitigate infection risks in healthcare settings.